The present invention generally relates to a photographic system in which desired photographing functions are effected while signals are applied or received between a camera body and camera accessories such as an interchangeable lens, an extension ring, a motor-drive unit, an electronic flash, etc. which are mounted on or attached to said camera body, and more particularly to a camera system for deriving fixed memories stored in the respective accessories.
Generally, in a high class photographic camera such as a single lens reflex camera and the like, it has been so arranged, in many cases, that, with camera accessories such as the interchangeable lens, motor-drive unit, electronic flash unit, etc. coupled to the camera body, functionings of the respective camera accessories are controlled by a control system provided at the side of the camera body or an arrangement provided within the camera body is controlled based on information from the camera, accessories. In the latter case as described above, if various data of the respective camera accessories are adapted to be transmitted electrically, coupling portions between the camera body and the camera accessories may be simplified for convenience in use, as compared with mechanical signal transmission conventionally adopted.
Meanwhile, it has been recently proposed to effect control of the camera body and camera accessories by a microcomputer, and in the above case, there may be conceived an arrangement in which with a fixed memory circuit such as a ROM (read only memory) provided in each of the camera accessories so as to keep data specific to the camera accessory stored therein, an address within the fixed memory circuit is designated from the side of the camera body for reading the data of the designated address into the camera body.